A technology has been proposed in which mobile objects that are occasionally concealed are detected from images and the detection result is displayed. In this technology, for example, regarding a person who is captured to be freely walking in surveillance camera images, the positions of the face of that person are estimated from the part of movement within the screen. However, if the face is not detected at the estimated positions, then it is determined that the person is concealing his or her face; and display control is performed in the form of zooming in the face part.
However, in the conventional technology, there are times when it is not possible to confirm a concealed target. For example, in a face detector, an upper-body detector, or a human detector; the supposed position of a face is sometimes erroneously determined regardless of the fact that no face is present, or a face is erroneously determined to have been concealed regardless of the fact that the face is not concealed. Hence, such erroneous determination sometimes makes it difficult to confirm the persons who are concealing their faces.